Loudspeaker enclosures which have sharp exterior edges at or within the periphery of the baffle produce undesirable audible edge diffraction which manifests itself as audible secondary point sources.
Edge diffraction occurs at all points along any sharp edge at or within the periphery of the baffle's exterior surface. When the length between 2 edge points is equal to the 2π to 4π conversion length, the edge diffraction will be audible as a second point source 90 degrees out of phase with the driver source. This phenomenon is described as incoherent phase response although it is commonly referred to as “muddy sound.” It is caused by there being two different arrival times for the same frequency to the listener, both of which are audible. Incoherent phase response is multiplied if the driver is centered between any two points along the baffle's exterior surface edge.
Loudspeaker enclosures which have an interior pair or pairs of parallel surfaces with equal dimensions multiply sound waves, creating standing waves. Standing waves undesirably increase or decrease the amplitude of select frequencies, based upon the dimensions of the pair or pairs of parallel surfaces.
Standing waves are multiplied by rectangular or cubic loudspeaker enclosures due to the presence of two or four sidewalls having an equal area inherent to their design. The frequency coinciding with the pair or pairs of equally sized walls is multiplied, creating peaks or decreased, creating nulls. These anomalies cause very audible tone coloration and irregular frequency response.
Traditional loudspeaker enclosure design features used to reduce standing waves include batting material to reduce the amplitude of the standing waves and bracing on the interior surfaces. These solutions are less than optimal and typically increase the material and tooling costs associated with the manufacture of the loudspeaker enclosure.